Saw-tooth surface broach



'April 20,1948.4

w. J4. PHANEUF sAw TOOTH sRFAcE BRocH Filed Nov. 2, 1943 2simens-s'hee-'av 1 f www Wem# April 20, 1948. w; J. PHANEUF sAwl TOOTHSURFACE BRoAcH Patented Apr. 20, 1948 2,439,822 SAW-TOOTH SURFACE BROACHWilrose J. Phaneuf, Hudson, Mass., assigner to The Lapointe Machine ToolCompany, Hudson, Mass., a corporation of Maine Application November 2,1943, Serial No. 508,758

2 Claims. (Cl. 90-33) This invention relates to a surface type broachwhich is particularly vadapted to the formation of band saw teeth or tothe manufacture of other similar products having very sharp pointedprojections.

It is the general object of my invention to provide a broach for suchpurposes in which the breaching teeth may be of much more substantialconstruction than the sharp saw teeth which they produce. In suchbreaching teeth, I entirely avoid sharp points or narrow pointeddepressions.

vIn the carrying out of this invention, I provide abroach having aplurality of successive breach ing units, and With the cutting teeth ineach unit at double' thelinear pitch of the teeth to be produced. 'I'hebroaching units are so disposed in the broach that the cutting teeth insuccessive units are aligned in alternate series, whereby saw teeth ofthe desired pitch may be formed by the coaction of the cutting teeth insuccessive cutting units.

A preferred form of the invention is shown in the drawings, in whichFig. 1 is a plan view of my improved breach;

Fig. 2 is a partial side elevation thereof;

Fig. 3 is an end view of the broach;

Fig. 4 is a planv view of a pilot block;

Figs. 5 and 6 are side and end views thereof;

Fig. 7 is a plan view of a shearing unit;

Figs. 8 and 9 are side and end views thereof;

Fig. 10 is a plan view of a toothed cutting unit;

Figs. 11 and 12 are side and end views thereof;

Fig. 13 is a plan view of a toothed cutting unit of the alternateseries;

Figs. 14 and 15 are side and end views thereof;

Fig. 16 is a plan view of a backing black;

Figs. 17 and 18 are side and end views thereof;

Fig. 19 is a diagrammatic view illustrating the operation of successivecutting teeth in the formation of the saw teeth; and

Fig. 20 illustrates the assembly of the pilot block and cutting units.

Referring to Figs. 1, 2 and 3, my improved breach comprises a basemember 20 adapted to be secured to the plunger or ram of a surface typebreaching machine, preferably but not necessarily of the vertical type.A plate 2| is secured to the base member 20'and is iirmly'held fromdisplacement by a longitudinal key 22 and a cross key 23. The plate 2|has upstanding flanges 25 and 26, spaced apart to receive a pilot block21, a plurality of shearing units 28, and a plurality of alternatelydisposed toothed cutting units and 3|.

The pilot block and the shearing and cutting units are held in positionbetween' the flanges 25 and 26 by clamping bars 33 and 34 which projectinward over end lugs Von the block 21 and on the units 28, 30 and 3|.Clamping screws 36 s are provided in the flange 25 and engage the endsof the blocks and units to firmly seat them against the flange 25. Abacking block 40 is rmly secured to the plate 2| in recesses 4I and 42in the flanges 25 and 26 and resists the end pressures of the shearingand cutting units during the broaching operation.

I will now describe the detailed construction of the pilot block 21, theshearing units 28, the cutting units 30 and 3 I, and the backing block40.

The pilot block is shown in detail in Figs. 4,` 5 and 6 and comprises asolid steel block having lugs or flanges 45 at its ends for clampingpurposes and having its upper front and back edges beveled as indicatedat 46 and 41. It will be noted that the ends of the block 21 are formedat a slight angle, shown in the drawings as being 7. This angle is forthe purpose of disposing the cutting edges of the shearing and cuttingunits at asimilar angle to the line of broach travel, thus producing aslight shearing cut.

It will also be noted that the right-hand edge of the block 21, asviewed in Fig. 6, is cut back at an angle of 3. This incline coacts withthe shearing and cutting units to provide necessary clearance or relief,as will be explained. The height of the pilot block is made slightlyless than the` height of the first shearing unit 28.

One of the shearing units 28 is shown in Figs. 7, 8 and 9. It isprovided with end lugs or projections 41 for clamping purposes, with acutting edge 48, and is cut away at 7 on the ends to match the pilotblock and to produce a shearing cut. The unit 28 is also cut away at 3on the bottom, so that it may coact with the inclined side surface ofthe pilot block 21 and provide clearance or relief for the top surface49 which engages the work ai; the cutting edge. A plurality of theseshearingunits, such as 6 or 8, is provided and the units progressivelyincrease in height by very small increments, such as 0.001" per unit.

The function of the shearing units is to accurately size the stockbefore the cutting operation begins. In the ordinary use of the broach,a large number of strips of stock are superposed and clamped in positionand are sheared and cut at a single stroke.

One of the cutting units 30 is shown in Figs. l0, 11 and 12 andcomprises a member which is in general quite similar to one of theshearing ting units.

units 28 and which is similarly provided with end flanges and withcut-away or inclined end and bottom faces. The top face of the cuttingunit is provided with a plurality of teeth 50, spaced apart at doublethe linear pitch ofthe saw teeth to be produced. These teeth are ofsubstantial section and both the points and the roots of the teeth arerounded, as clearly shown in Fig. 19.

The teeth 50 are cut at an angle of 5, as indicated in Fig. 10, so thatthe end angle of 7 provides a slight clearance or relief for the teethon their cutting faces.

One of the cutting` units 3l is shown in Figs. 13, 14 and 15. This unit3l is identical With the unit 30 previously described, except that theteeth I are staggered one-half space lengthwise with respect to theteeth 50 in the unit 30.

The backing block 40 is shown in detail Vin Figs. 16, 17 and 18 and isprovided with a face 53 formed at a 7 angle in plan and at a 3 angle inelevation.

In assembling myimproved broachrfrom the unitsshown and described, thepilot block 2l is placed at the left or entering -end of the breach asshown in Figs. l and .20. A succession of .shearing unitsZB ofprogressively increased height are then assembled against the blockZ'l,,and these shearing units are followed by asuccession of cutting units39 and 3l, alternately disposed.

The cutting units 30 provide teeth .of gradually increasing height inone set of lineal vseries and the units 3l providecutting teethof'gradn'ally increasing height in an alternately :disposed set oflinear series.

The progressive increase in tooth height may be on" the order of one andone-'half thonsandths of an inch per unit, .and each series of units 30and 3l may` comprise 25 or more separate cut- The last two or threeunitsin each series are preferably of uniform height, for a iinai sizingelect.

The manner in which the .cutting teeth 50 and 5| produce the desiredsharp-pointed saw teeth is made clear in Fig. .19, which shows portionsof cutting units 30 and 3| coacting with a strip of saw stock S. Theteeth 50 ofthe unitsz30 remove the stock in the sectioned areas a inVsuccessive increments, and the teeth .5I in the unitsi similarly andalternately remove the stock in the unsectioned areas b. The stockportions c which are left between these removed areas'a and `b form theteeth of the saw. It will be noted that one side of veach tooth isformed .by avv tooth 50, while the other side of the tooth 'is formed bya tooth 5l. Thus neither tooth is required to have a sharp point or asharp root.

The teeth 50 and 5I may thus be of such size and contour that they will`resist wear and will remain in effective operation for long periods.The shearing and cutting units kmay be sharpened when necessary bygrinding on their cutting edges, indicated at 48 in Fig. 9 and at 51 inFig. 12.

By the use of my improved breach, together 4 with suitable clamping andfeeding devices, band saw teeth may be cut in a surface broachingmachine with great accuracy and with extreme rapidity and greatlyimproved and increased production may be achieved.

Having thus described my invention and the advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claims, but what I claim is:

1. In a surface broach comprising a plate having side anges and acontinuous recessed ilat cutter-supporting surface, a plurality ofsubstantially rectangular elongated toothed cutting units each havingits top face substantially at to the parallel front and back faces ofsaid unit and having its bottom face angularly disposed to form anincluded angle with the front face of said unit ofv slightly less than90, and means to align and position said units between said side ilangesin said breach and with the bottom faces of said units seated againstsaid continuous recessed surface Yof said vbroach 4and with :said unitsthereby rearwardly inclined in 'accordance with said slight angle,whereby each cuttingl unit is relieved on its top surface.

2. A surface broach for breaching `sharply pointed saw teeth comprisinga fiange'd'plate and a plurality of separate toothed *.cuttingnnitssecured therein, all of the cutting .teethin :said units havingsubstantially rounded ltupsi and roots and said teeth being. spaced.apartzn said units double the saw'tooth pitch, the tethin one-half ofsaid-units being ,staggered .one saw tooth space with respect-tothefteeth in the remaining cutting units, said units beingalter natedsuccessively in said ang'ed plate `to dis'- pose the teeth in alternateparallel linearV series, andthe cutting edges Y.of the'teeth insuccesasively adjacent units having their. lines of breaching actionintersecting at lthe saw-'tooth points and relatively remote from theirrounded tops and roots.

WILROSE .1.1 PHAN-EUF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,173,074 Romaine Sept. 12, 19392,204,537 Lapointe et al .June 11', 1940 28,508 Schutte May 29, 1860330,499 Laybolte Nov. 17, 1885 1,932,223 Lindquist Oct. 24,' 19331,776,711 Unger Sept. '23, 1930 1,979,973 Halborg Nov. 6, 1934 180,409Alvord Aug. 1, 1876 1,275,006 Eden, Jr. Aug. 6, 1918 1,440,933 Perkinsetal. Jan. 2, .1923 1,589,901 Roberts June 22,. 1926 1,935,774 HalborgNov. 21, 1933 2,250,392 Phaneuf July 22, 1941

